I have finished that image, but, well, i think i´m not pretty happy with that...i tried to make a "comic" effect, but, not too much. I tried to make the guy "strong" (so i didn´t make a noticeable neck and i made big legs).

is he supposed to be 'strong' like he can break you with one hand, or 'strong' like he's sort of chubby but there's a lot of meat under the fat? i think you could have gotten a good impression of strength if you'd made the gut and legs just *slightly* thinner...but this way looks good too. it depends on exactly what sort of 'don't fuck with this guy' you were after.

I want to say too that the arms are anatomically (is it spelt like this in English?) incorrect. The shape of the right biceps isn't natural, and the triceps have no shape at all (and they should appear, as the arm is extended).
DDrake, you could have put the "acueducto" behind the man, it might be cool!